s4-dsdb: Take more care in handling of global schema memory

s4-dsdb: Take more care in handling of global schema memory

This reworks dsdb_replicated_objects_commit() to have a proper local tmp_ctx and
to be more careful about what schema is set (only setting a global schema if
the original schema was global).

In particular, the new working_schema is not given a talloc reference
to the old schema.  This ensures that the old schema can go away when
no longer used.

Andrew Bartlett

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Sat Aug 11 10:31:57 CEST 2012 on sn-devel-104